SLVSA30D April 2011 – March 2019 UCD9090
PRODUCTION DATA.
A GPIO pin can be used to coordinate multiple controllers by using it as a power-good output from one device and connecting it to the PMBus_CNTRL input pin of another device. This configuration creates a master-slave relationship among multiple devices. During the startup operation, the slave controllers initiate the start sequences after the master controller has completed its start sequence and all rails have reached regulation voltages. During the shutdown operation, as soon as the master starts to sequence-off, it sends the shut-down signal to its slaves.
A shutdown event on one or more of the master rails can initiate shutdown events of the slave devices. The master shutdowns can be initiated intentionally or by a fault condition. This method coordinates multiple controllers, but it does not enforce interdependency between rails within a single controller.